Initially the Fourth Crusade was intended to overthrow the Muslim controlled Jerusalem by invading Egypt. In April 1204, the crusaders of Western Europe attacked and encroached the Christian city of Constantinople which was the capital of Byzantine Empire.

This was between the Eastern Orthodox Church and Roman Catholic Church and was the final acts in the Great Schism. In 1204 to 1261 the crusaders established the Latin Empire along with other Latin states in the Byzantine lands they overpowered.

There was diminished interest in Europe against the Muslims after the limited success of the Third Crusade. Jerusalem was lost to the Ayyubid dynasty, which controlled all of Egypt and Syria, and only few cities were still held by the crusader Kingdom of Jerusalem. The Third Crusade set up a kingdom on Cyprus. In 1198, Pope Innocent III accomplished the papacy, and the teaching of his beliefs of a new crusade became the main goal of his approach.

He was ignored by the European monarch, England and France were in warfare against each other and the Germans were struggling to cope against Papal power. However a crusading army was organised at a tournament in Ecry by Count Thibaut of Champagne in 1199. Thibaut was announced as leader but tragically died in 1200 and Boniface of Montferrat and Italian took his place. Boniface sent ambassadors to Genoa, Venice and other states to negotiate a contract for transport to Egypt. The main object of their crusade was one of the ambassadors, the historian Geoffrey of Villehardouin.

Genoa showed no interest but negotiations were opened in Venice in March 1201, agreeing to transport 33, 500 crusaders. The Venetians took a full year to prepare and build ships and train the sailors and restricted the city's commercial activities. The army set out of Venice in October 1202 and originally started from areas within France.

The army also comprised of men from Champagne, Amiens, Blois, Saint-Pol, Burgandy and lle-de-France. Other groups of men came from the Holy Roman Empire, which consisted of men under Bishop Martin of Pairis and Bishop Conrad of Halberstadt, along with Venetian sailors and soldiers led by doge Enrico Dandolo. On June 24, 1202 the crusade was ready to set sail and head towards, Cairo the Ayyubid capital.

This agreement was authorised by Pope Innocent, which included a serious ban on any attacks made towards Christian states. The outcome of the crusade was that almost none of the crusaders made it to the Holy Land and the Latin Empire and drained off most of Europe's crusading spirit and vigour.

The Legacy that was left by the Fourth Crusade was a sense of deep betrayal the Latin’s had instilled in their Greek coreligionists separation between the Church in the East and West was strengthened. The Fourth Crusade was one of the last of the crusades launched by the Papacy, however falling quickly out of Papal control. The Crusades became economically and politically effective for Crusaders who were more motivated to follow ambitious and worldly principles rather than a spiritual one.